Forza Horizon 6 hands you a sentence and a photo each week. The sentence names a category of place, which on a map this size narrows nothing. The photo is where the location actually lives.
Shadow direction, time of day, horizon line, whether there is coast or ridge in shot. Taken in the order that eliminates the most map per glance: reading the photo clues.
A different problem, and not one you caused. Finishing the qualifier and getting nothing is usually season rollover or unsynced progress. Fixes ordered by likelihood: treasure hunt not working.
Since the clue rotates out weekly, the current week's decoded location is the page worth keeping open rather than any static guide.